In this NASA Phase I STTR effort, the feasibility of fabricating isolated ridge waveguides in 5% magnesium-doped lithium niobate (5% MgO:LN) will be established. Ridge waveguides in MgO:LN will significantly improve the power handling and conversion efficiency, increase photonic component integration, and be well suited to space based applications. The key innovation in this effort is to combine recently available large, high photorefractive damage threshold, z-cut 5% MgO:LN with novel ridge fabrication techniques to achieve high optical power, low cost, high volume manufacturing of frequency conversion structures. The proposed ridge waveguide structure should maintain the characteristics of the periodically poled bulk substrate, allowing for the efficient frequency conversion typical of waveguides and the high optical damage threshold and long lifetimes typical of the 5% doped bulk substrate. The low cost and large area of 5% MgO:LN wafers and the improved performance of the proposed ridge waveguide structure will enhance existing measurement capabilities as well as reduce the resources required to achieve high performance specifications. For these reasons, the development of ridge waveguides in 5% MgO:LN directly addresses NASA's Innovative Sensors, Detectors and Instruments for Science Applications, STTR subtopic T4.01: Lidar, Radar and Coherent Fiber Bundle Arrays.